Vinyl floors or floor coverings, the composition of which is particularly based on a polyvinyl chloride (PVC) lining, are well-known today as replacements for linoleum coverings due to their impermeability, resistance to abrasion, and chemical agents, as well as their non-slip and easy-to-clean properties. Therefore, such lining is extremely suitable for high-traffic areas that require frequent cleaning, such as kitchen, bathroom or children's playroom floors.
In addition to being characterized by their composition, vinyl linings are characterized by being provided with a decorative layer imitating typical linings ranging from those that look like wood, granite or ceramic, to others having more cutting-edge designs that can be obtained by printing any design with different drawings, patterns and colors.
These vinyl linings are found on the market mainly in two formats, i.e., in the form of tiles or boards and in the form of continuous rolls. Linings in tile format are more useful if a part experiences any deterioration because it is only necessary to replace the tile in question and not the entire sheet of the roll.
With respect to placement, vinyl linings in the form of a tile require the application of a dispersion adhesive, gum or glue on the surface to be placed in contact with the floor, although for some time now tiles sold on the market have a self-adhesive layer protected by a sheet of paper that can be peeled off for direct application on the surface of the floor covering or floor to be covered. Vinyl tiles with a perimetral anchoring system for being installed directly on a subfloor can also be found on the market. Such tiles can be installed in a floating manner, i.e., simply connecting the parts to one another without having to adhere them to the surface.
It must be pointed out that vinyl linings have the drawback of having very poor dimensional stability because heat and temperature changes greatly affect them. Therefore, in adverse conditions of heat exposure, a vinyl tile will experience an expansion effect of up to 0.15% with respect to its initial size at room temperature of ±23° C. It can also bow and deform, losing its initial planimetry and therefore becoming detached from its support, or it can become disconnected from adjacent parts in the case of a floating installation. Vinyl linings are therefore unsuitable for floor coverings in installations where there are marked temperature changes (≥15° C.). Cold temperatures also significantly affect the dimensional stability of vinyl, being able to experience a shrinkage effect of more than 0.2% with respect to its initial size at room temperature of ±23° C. Generally, any installation having vinyl floors, particularly those installed in a floating system, must remain at a constant temperature of between 15° C. and 25° C.
To prevent stability problems caused by heat, there are mixed or composite vinyl linings in which the vinyl material is attached directly to a rigid or semi-rigid main layer or substrate having a certain constant thickness, such as cement or fiberglass-reinforced cement, known as fibrocement, thus forming a multilayer lining plate. Fibrocement has an excellent dimensional stability that remains unchanged in response to humidity or temperature changes, and the dimensional stability of fibrocement is ten times higher than the stability of vinyl material.
Nevertheless, the introduction of rigid or semi-rigid materials in the multilayer panel complicates and even prevents being able to actually connect the panels to one another since it is impossible to make any type of male-female groove on the edges of the panels without breaking a portion of the panel. Therefore, the panels either have no grooves and are arranged independently from one another, without acting as a uniform whole, or a groove must be molded together with the fibrocement layer, which makes the lining panel manufacturing process more expensive and longer since it is necessary to arrange molds for the grooves and to manufacture the main layer of the panel by pouring the fibrocement and waiting for it to set, without being able to use prefabricated fibrocement plates for that purpose.
Another added drawback of such multilayer plates is that the rigid or semi-rigid main fibrocement layer has caused difficulties in placing the multilayer lining plate on floors since ductility of the vinyl tile has been lost due to the attachment thereof to the rigid fibrocement layer.
Therefore, vinyl tiles could be easily applied on floor coverings or floors even though their finish is not completely smooth since vinyl is a ductile material that adapts to the imperfections or irregularities that the surface to be lined may have. Nevertheless, by having attached the fibrocement support layer, the resulting panel can hardly adapt to said irregularities and produces a “smacking” effect, a type of noise and certain vertical movement that occur when walking on the panel since the plate is usually only supported by three of its four corners, and upon stepping on the other corner, the plate moves as if it were a lever.
This effect means that floor coverings or floors should not be lined with mixed vinyl and fibrocement plates if they are not completely level and if they have no type of irregularity, which is very hard to find.
Leveling a floor and making sure that its surface is smooth and completely planar involves work and considerable implementation time that is hard to take on, counteracting the placement advantages linked to a vinyl material. Furthermore, in most cases in which the vinyl lining projects from a pre-existing, generally tiled, floor, it is common to find some edges or corners of tiles protruding with respect to adjacent tiles, whereby the lining with a mixed vinyl and fibrocement plate such as those described would only further increase the effect of irregularities due the difference in level, causing a disastrous result from both the aesthetic viewpoint and the personal safety viewpoint.
Based on the foregoing, it would be desirable to have a multilayer lining plate that is dimensionally stable under temperature and humidity conditions, that can be connected with adjacent plates so that the lining acts as a whole, and that is optionally capable of adapting to horizontal surfaces even though these surfaces do not have a perfectly horizontal and smooth finish free of irregularities.
Non-Limiting Overview of the Invention
In order to provide a solution to the drawbacks that have been considered, the present invention discloses a multilayer lining plate for essentially horizontal support surfaces such as floors or floor coverings. It must be pointed out that an essentially horizontal support surface is understood as all those surfaces in contrast to vertical surfaces, such as wall surfaces, so they also include surfaces having a certain inclination, such as ramp surfaces.
The multilayer lining plate object of the invention has a main layer, having at least two longer sides and two shorter sides, including at least one part, and a ductile or flexible upper decorative layer. Preferably, the main layer has a rectangular shape.
The multilayer lining plate object of the invention has along an outer edge of each of the longer sides of the main layer a ductile machinable portion that can be machined to form a connecting profile for connecting the plate with other plates, wherein the at least one part of the main layer is more rigid than the upper decorative layer; and wherein the at least one part of the main layer is preferably made of magnesium oxide, fibrocement or mortar with or without perlite and/or vermiculite and/or cellulose. According to the preferred embodiments, the main layer comprises magnesium oxide with perlite, vermiculite and cellulose. Perlite provides lightness, vermiculite improves fire resistance and cellulose provides continuity, avoiding the breakage of the material.
The inventors have found that it is enough to provide the machinable portions along the outer edge of the longer sides of the main layer in order to be able to form therein a corresponding connecting profile for the connection with other plates by facing the long sides of the plates.
The plates are rectangular and elongated, for instance 20 cm×150 cm, 305 cm×610 cm, that is to say, there is a significant difference between the shorter sides and the longer sides (proportions of 1:7, 1:2, etc.). With these proportions, only part of the perimeter of the main layer can have machinable portions along part of or the whole of the longer sides. It is also possible to have machinable portions along part of or the whole of the shorter sides have. It can be sufficient for the short sides to have machinable portions at their ends that result from the ends of the continuous machinable portions along the outer edge of each of the longer sides of the main layer. Thus, the machinable portions ensure that a connecting profile can be performed along the edges of the longer sides of the plate and it can be tried to perform a connecting profile directly in the outer edges of the shorter sides. There is a risk that the connecting profiles in the main layer can be deteriorated or can break when they are performed directly in the shorter edges of the main layer, but in this case, the plate will allow a good connection with other plates because there is machinable portions in the long sides (which are the sides that take on most of the load) and in end areas of the short sides.
According to a feature of the invention, the machinable portion is made of medium-density fiberboard (MDF), a wood-plastic composite (WPC) material or polyvinyl chloride (PVC).
According to another feature of the invention, the decorative layer is a layer of natural or synthetic plant-based material, mineral-based material, organic material, inorganic material or a mixture thereof, although according to a preferred embodiment, it is a sheet of vinyl material having a thickness comprised between 1 and 10 mm.
According to another feature of the invention, the part or parts of the main layer are made of magnesium oxide, fibrocement, also referred to as natural or synthetic fiber-reinforced cement, or mortar with perlite and vermiculite, and the thickness of the main layer which is made of magnesium oxide, fibrocement, also referred to as natural or synthetic fiber-reinforced cement, or mortar with perlite and/or vermiculite and/or cellulose measured in the normal direction with respect to the surface of the decorative layer is equal to or greater than 2.5 mm. In addition to providing strength to the plate, these materials have high dimensional stability since they absorb water or humidity without swelling or changing their dimensions.
Plates with wood or wood-based cores can have bad behaviour related to their dimensional stability in response to humidity.
In accordance with the current regulations for modern synthetic flooring, plates for horizontal support surfaces such as floors or floor coverings must be tested to determine their dimensional stability. According to this test, a plate must be heated until an extreme temperature and then coming back to a stabilization temperature, this is to say, a plate, which is initially at 23° C., is heated at 80° C. for 360 min and then, heat stops and the plate comes back to the temperature of 23° C. This test is intended to measure the planimetry of the plate in a situation wherein a sunbeam goes through the glass of a window, heating a certain area of the plate to an extreme temperature (magnifying glass effect).
The inventors have carried out tests to determine the dimensional stability of a plate according to the invention, particularly with embodiments wherein the main layer is made of magnesium oxide and has a thickness of about 4 mm and the decorative layer is made of PVC with a thickness between 1.8 and 2 mm, and the dimensional stability of a plate made of WPC and vinyl. The results show that the dimensional stability of the plate according to the invention has an average curling of 0 mm and an average dimensional change of 0.10%, whereas the WPC and vinyl plate shows that the curling is too obvious and it could not be measured, and a dimensional change of 2.85%. Therefore, it is clear that the plate according to the invention has a dimensional stability far better than wooden or wood-based plates, even with a decorative layer of vinyl.
With regard to vinyl and polymer flooring plates, they show a right dimensional stability, because although they are heated, they are not deformed and come back to their original dimensions.
However, the determination of the dimensional stability does not inform about the behaviour of flooring plates when they are at a temperature lower than 23° C.
Therefore, although vinyl linings or plates of plastic may pass the above explained test, it does not mean that these plates are going to behave properly in daily life conditions. The inventors recognize that the floor in a room is rarely always at 23° C. In summer time the flooring plates can remain at 45° C. for long periods and in winter they can remain at 5° C. if one considers, for instance, the plates in an industrial plant. There is no regulation to test the variation in the dimensions of a plate in these conditions, although in daily life, the expansion coefficient and the contraction coefficient of flooring plates play a crucial role, according to the professional experience of the applicant.
The inventors are aware of the high importance of the expansion coefficient and the contraction coefficient of flooring plates because they have observed the significant problems that can arise when plates have high coefficients. If the expansion coefficient is high, it means that the length of the plate increases and a plate can collide with the next one, the male connection profile penetrates into the female connection profile of the next plate and can raise and break one of the tabs of the female connection profile.
If the contraction coefficient is high, it means that the length of the plate decreases and the distance between two plates increases, that is to say, the joints open. In cold temperatures, this is what happens with PVC plates.
Since the inventors have detected the great important of these coefficients, they have tested a plate according to the invention and a resilient flooring plate (resilient flooring plates are those made of WPC, PVC and copolymers) to determine such coefficients by creating the following procedures.
The expansion test involves: a) stabilizing the sample of the plate at 23° C. and measuring its dimensions, b) heating the sample plate to 40° C., stabilizing it and measuring its dimensions, and c) allowing the sample plate to cool, stabilizing at 23° C. and measuring its dimensions.
The contraction test involves: a) stabilizing the sample of the plate at 23° C. and measuring its dimensions, b) cooling the sample plate to 5° C., stabilizing it and measuring its dimensions, and c) allowing the sample to heat, stabilizing at 23° C. and measuring its dimensions.
According to the results, the plates according to the invention have an expansion length average at 40° C. of about 0.105 mm/ml (ml is linear meter) and a contraction length average at 5° C. of about 0.472 mm/ml. On the other hand, the resilient flooring plates made of vinyl have an expansion length average at 40° C. of about 1.282 mm/ml and a contraction length average at 5° C. of about 1.192 mm/ml. Therefore, the comparison of the results show that the plates according to the invention have far better expansion and contraction coefficients than resilient flooring plates. It must be said that the coefficients with WPC plates are similar to the ones of vinyl plates.
The differences between the expansion and contraction behaviour are more than significant, clearly showing that the plates according to the invention have a better behaviour and do not suffer from the problems explained before.
Additionally, vinyl plates usually measure 1 m or 1.20 m and they are tending to extra-large formats. The plates will get irreversibly deformed. Vinyl has two negative effects when heated: (1) expansion and (2) it becomes weaker from a structural point of view. At 40° C. it softens so much that a person can bend it with his hand, it seems like a chewing gum. In order to make a connection system between plates work, there has to be at least a minimum rigidity.
The plate according to the invention expands much less, is more rigid and therefore, is not so structurally vulnerable when it is subjected to movements by thermal differences heat-cool.
The vinyl plates alone cannot push, because when a plate is heated, it is soft and therefore cannot push the plates next to it in order that the end of the flooring moves and reaches the expansion joint (for instance the joint next to a wall. When vinyl plates are heated, they cannot move the plates next to them. The movement is impossible because plates have been softened due to the heat, and instead of moving, the plates do not find space to expand themselves and they get curved.
On the other side, when the temperature is low, the vinyl plate wants to become smaller, but in a flooring system, one plate is connected to the other one by the connecting profiles. With cooling, plates are separated but instead of pulling to the plates which are next to them, plates get separated when the first plates shrink because the tab of the connection profile also shrinks.
The problem detected by the inventors related to expansion and contraction behaviour of the floor plates in daily life conditions has been solved by the multilayer plate of the present invention. The plate shows a good behaviour and does not suffer from the problems explained above, due to having been able to combine the cited materials in order to have low expansion and contraction coefficients. Preferably, the main layer and the machinable portion have a thickness measured in the normal direction with respect to the surface of the decorative layer comprised between 3 mm and 10 mm.
According to one embodiment of the invention, the main layer is configured by a plurality of individual parts arranged adjacent to and facing one another by at least one of their side faces. The individual parts can be rectangular prismatic parts having planar and vertical side sides, and they can be separated from one another leaving a small empty space or a strip of a compressible or spongy material can be arranged in said space.
According to another feature of the invention, the multilayer lining plate can further comprise, arranged below the main layer, a continuous and flexible support layer, preferably of polyvinyl chloride (PVC), a wood-plastic composite (WPC) material or high-pressure laminate (HPL), in this case only when the main layer is manufactured by a single part made of a rigid or semi-rigid material. The support layer provides certain flexibility to the multilayer assembly while at the same time reinforces the lower portion of the plate, which is quite necessary in those plates in which the machined connecting profiles in the ductile machinable portion usually have a very small thickness in the lower portion thereof. The support layer preferably has a thickness equal to or greater than 0.25 mm and less than or equal to 5 mm. Particularly when the support layer is of PVC or HPL, the thickness is usually comprised between 0.3 and 1.5 mm, whereas with WPC the thickness is usually equal to or greater than 3 mm.
According to another feature of the invention, in the lining plate the outer face of the machinable portion oriented opposite the main layer is formed as a connecting profile for the connection with other plates, which results from having machined the mentioned profile in the machinable portion provided for such purpose.